The Medicines Health Regulatory Agency (MHRA) has issued a safety update on blood monitoring in patients being treated with antipsychotic medications, after coroners raised concerns about two deaths.
The MHRA says it has received two separate reports from coroners regarding the need for monitoring of clozapine blood levels in one report and monitoring antipsychotic blood levels during long-term high-dose antipsychotic use in the other.
In the first report, the individual's death was determined to have been caused by clozapine toxicity, pneumonia and treatment-resistant schizophrenia. In the second report, the death of a patient on long-term high-dose antipsychotic treatment was determined to have been caused by coronary artery atherosclerosis and amisulpride toxicity. In both cases, the MHRA was asked to take action to prevent further deaths.
The MHRA says expert advisory groups of the Commission on Human Medicines have considered the safety data for clozapine and other antipsychotic drugs and is now advising the following:
1. Monitoring blood clozapine levels for toxicity is now advised in certain clinical situations such as when:
- a patient stops smoking or switches to an e-cigarette;
- concomitant medicines may interact to increase blood clozapine levels;
- a patient has pneumonia or other serious infection;
- poor (reduced) clozapine metabolism is suspected; and
- toxicity is suspected.
2. If blood clozapine level monitoring is carried out, this should be in addition to the required blood tests to manage the risk of agranulocytosis.
3. For other antipsychotics, where assays and suggested reference values are available, blood level monitoring for toxicity may be helpful.
References: Drug safety update: Clozapine and other antipsychotics: monitoring blood concentrations for toxicity. Medicines and Healthcare products Regulatory Agency. 2020 August 26.
This article originally appeared on Univadis, part of the Medscape Professional Network.
